To be able to run PrEd, Java 1.4 or higher must be installed. Also the JAVA_HOME environment variable must be set, so PrEd can work properly. Unzip the ZIP file downloaded into the preferred location and execute pred.bat under MS Windows and pred.sh under Unix variants.

After starting PrEd, one can open a file by either using the menu or using the Ctrl+O keyboard combination. Select the JAR or WAR file (or an other type of compatible ZIP archive). The application will extract the selected file to the temporary extraction folder (defined in the preferences dialog). The main window will then display all property files found. Depending on the preferences set, either XML files, property files or both are shown.

Each file can be edited by double clicking its entry in the table showing all files found. By double clicking such entry, a dialog is displayed to edit the values of the selected file. To update the JAR or WAR file with the edited files, the Update Archive button should be pressed. Note that all changes to the property files have no effect on the archive till the moment the update button is pressed. Then the old archive is replaced with a new one containing the files changed.

PrEd also supports nested archives. A nested archive, such as an EAR file, contains one or more JAR, WAR or other types of ZIP files. To edit such nested archive, click on the Open nested archive menu item. After selecting the archive containing the nested archives, a dialog is shown, which provides a list of all archives found. Select the nested archive, which needs to be altered. PrEd searches within the archive for files with the .jar, .war, .sar and .zip extensions, if you want to add other ZIP compatible files, add them in the preferences screen. Note that in case of a nested archive, the update button in the main window, as described in the Getting started section, will update both the nested as well as the parent files.

A property file can be edited by clicking on the property names and changing their corresponding values. All changes are applied directly to the property file. No need for explicit save actions. All changes are stored locally. To stop editing the property file, press the close button and the main application window reappears.

The XML properties file editor provides with a hierarchical view of file's contents. In this overview all nodes can be double clicked, but only the leaf nodes (text nodes) can be edited. Also all attribute values can be edited by double clicking them. Note that attributes are denoted by a and XML nodes by a . If an editable node or attribute is clicked, the following dialog appears. In this dialog the value can be edited. All changes have immediate effect on the local XML file. After updating the archive, as described in Getting Started, the changes have also effect in the original archive.

The preferences dialog can be found through the file menu. In this dialog, the temporary extraction path can be set. Click on the browse button to select a new extraction path. The type of files which is searched for can also be set here. You can also add or remove here the extension of files, which should be searched for within an archive, in case of opening a nested archive (such as an EAR file). All file type extensions are case insensitive. Only JAR compatible files should be added to this list.
After pressing the save & close the settings will apply for all files which are going to be opened. Note that if you want to see an different type of files, you will need to reopen the archive.

• If the ZIP archive contains entries with OS reserved characters, it will not be able to extract the archive. For example, if the archive contains files with an absolute file path with drive letters and such, the file will not be able to be created. Basically, everything that can be extracted using Sun Java's jar application, can be regarded as a valid archive.